Stung by criticism of their role in newly revealed government surveillance programs, Google (GOOG) and other leading Internet companies responded Tuesday by calling on federal authorities to let them tell the public more about the National Security Agency’s secret efforts to gather data on Internet users.

The new response from Google, Facebook and Microsoft came as a coalition of civil liberties groups urged Congress to conduct a broad investigation of the government’s data-gathering, the ACLU filed a lawsuit challenging a separate surveillance program involving phone records and a poll showed that Americans are sharply divided over whether such surveillance is justified.

Being required to keep government requests secret is helping fuel speculation that Google is giving the government “unfettered access to our users’ data,” complained David Drummond, the company’s chief legal officer, in a blog post. He added that news reports to that effect “are simply untrue.”

Civil rights activists called the Silicon Valley companies’ statements “a good start,” but some said the companies should do more to support a full investigation of the data-gathering efforts.

Apple (AAPL), Facebook and Google denied knowledge of the NSA program known as PRISM when it was first disclosed last week, while acknowledging they comply with what they consider lawful government requests for information.

Google followed up Tuesday by announcing it has asked the FBI and Department of Justice for permission to begin reporting how many data requests the company receives from the government under the Foreign Intelligence Security Act, which currently requires companies to keep those requests secret.

Facebook and Microsoft later echoed Google’s request, saying they want the government to allow more disclosure about data requests. Google and Microsoft already report how often they receive certain types of requests, such as law enforcement subpoenas, without disclosing specifics. Facebook said it would issue a similar report if it could cover all requests.

Among other Silicon Valley companies named in initial reports about PRISM, Apple and Yahoo (YHOO) declined to comment on Google’s letter.

Twitter general counsel Alex Macgillivray, meanwhile, posted a tweet saying he agreed with both Google and Oregon Sen. Jeff Merkley, who is pushing to declassify rulings of the secret Foreign Intelligence Surveillance Court. Twitter wasn’t named on a list of companies participating in PRISM and has declined to discuss the program.

The companies’ statements were greeted with faint praise by civil liberties activists, who said the companies should join their coalition in calling for a Congressional investigation and broad reforms of intelligence laws.

“They have an obligation to their users, whose privacy has been compromised,” said Eva Galperin. a policy analyst with the Electronic Frontier Foundation, of Google and the other Internet companies. “This is the only way they can clear their name, given the scandal and lack of clarity over what kind of information they have been giving up to the NSA.”

The companies and the government have denied initial news reports that said the PRISM program gives intelligence agencies “direct access” to the companies’ servers. Instead, U.S. officials said the program operates within federal law to request information from the Internet accounts of foreign terror suspects and their contacts, although experts say that could include contacts in the United States.

Google went further on Tuesday, offering its first explanation of how it actually provides data that the government requests.

“When required to comply with these requests, we deliver that information to the U.S. government — generally through secure FTP transfers and in person,”said Google spokesman Chris Gaither, referring to File Transfer Protocol, a method of sending encrypted files over the Internet. “We refuse to participate in any program — for national security or other reasons — that requires us to provide governments with access to our systems or to install their equipment on our networks.”

In a poll over the weekend, the Pew Research Center found 56 percent of Americans would accept government tracking of phone records, but only 45 percent would allow monitoring of emails, if those efforts protect national security. About 41 percent rejected tracking phone records, and 52 percent opposed monitoring emails.

A leading tech trade association also voiced “grave concerns” about the government’s data-gathering efforts.

“In the effort to gather security data, the broader picture of the damage to the Internet was lost. Somehow the Internet as a global tool, a trade tool and a trusted communication tool for people around the world was not adequately weighed into the cost benefit analysis,” said Ed Black, president of the Computer and Communications Industry Association, which counts Google, Yahoo and Microsoft among its members.

While none of the big Internet companies joined the civil liberties groups in calling for a broad investigation and overhaul of surveillance programs, the coalition includes a few smaller firms, including the nonprofit Mozilla Foundation, which maintains the Firefox Internet browser.

The ACLU, meanwhile, said in its lawsuit that the NSA’s collection of phone logs from companies like Verizon, “is akin to snatching every American’s address book — with annotations detailing whom we spoke to, when we talked, for how long and from where.”

Contact Brandon Bailey at 408-920-5022; follow him at Twitter.com/BrandonBailey

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